# Tag Info

2

Lennard-Jones Parameters To quote the original source of those Lennard-Jones parameter values (Gordon and Kim), For all the systems involving atoms larger than helium, the predictions appear quite reliable... Our approach thus provides the first successful prediction of the intermolecular potentials for the rare gases (except helium) So I would not put ...

1

I'm not sure if coordination bonds as such are defined in the connectivity table in .sdf. Perhaps the original definition by MDL (back when operative)/Symyx have a line about this (still available from archive.org's snapshots by their Wayback Machine e.g., here).* While currently not functional for me, RDKit's cookbook includes a relevant entry to this, ...

-2

First of all, charged species are in general less stable than neutral species. So $\ce{O_2}$ will be the most stable species among them. In the next step compare their bond orders. The species with more bond order is more stable (in general). So next place goes to $\ce{O_2^+}$. Finally, in comparison of $\ce{C_2^+}$ and $\ce{O_2^-}$ both will have the same ...

5

Formal charge, like oxidation state, is fundamentally just a bookkeeping device (with a different counting method). This being so, formal charge can be correlated with an unequal sharing electrons between like atoms. In such cases it points to molecular polarity in situations where we would not ordinarily expect it. The classic example is ozone, $\ce{O3}$ (...

6

Formal charge is considered to be the charge present in one atom by considering all the bonds to be 100% covalent. The "charge present in one atom" is not a clear concept. A better way is to say "formal charge is the charge assigned to an atom symbol in a Lewis structure". This acknowledges that the formal charge depends on the choice of ...

3

Your problem seems to stem from confusing the number of linear independent basis functions(which is the same number as the size of the atomic orbital basis with which we started) and the number of all possible functions that can be built using this basis. Just as in a two dimensional vector space, where you have a maximum of two independent basis functions, ...

4

Yes, you are correct. The carbon-magnesium bond in a Grignard reagent is polar covalent with carbon being the negative end of the dipole, which explains its nucleophilicity and the magnesium-halogen bond is largely ionic. (image source)

2

Firstly, note that the labels $\sigma$, $\pi$, and $\delta$ aren't universally applicable to MOs; it depends on the molecular geometry. These labels are mostly useful for linear molecules. Non-linear molecules often have MOs that are labelled differently. Methane is a decent example. Other examples include water and ammonia. Restricting ourselves to linear ...

2

There are two things wrong with the premise. First, no one atom really makes any covalent bonds. A covalent bond requires at least two atoms, more if orbitals are delocalized. Second, manganese has not only two but seven valence electrons, which are plenty for bonding covalently to as many as four oxygen atoms. The additional valence electrons come from the ...

3

When you have atoms bonded all in one plane, there will be $p$ orbitals oriented perpendicular to the plane which may not interact significantly with adjacent atoms. Such orbitals would then be called nonbonding. We may compare water with carbon dioxide. Introductory textbooks often describe the oxygen as having a distorted $sp^3$ hybridization, but in ...

10

Most materials are available for the fall 2010 at http://chem125.webspace.yale.edu/indexFall10.html and for Spring 2011 (the last time the course was given) http://chem125.webspace.yale.edu the author is at j.mcbride@yale.edu

6

There is a webpage called Freshman Organic Chemistry I described as CHEM 125a. On the bottom of the page, there is a zip of all course pages $(\pu{10 MB})$. However, there are Terms of Use described in a separate page so you may need to donate money or pay for the usage. There is an age restriction as well: Use of Open Yale Courses website is restricted to ...

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I would add two points to MFarooqs' answer. First, I would emphasize that the basis for attractive van der Waals interactions is the polarizability of molecules. Polarizability is the property of having flexible charge distributions which may be distorted by interacting with charges outside of a molecule, leading to a more stable electronic state. ...

3

The so called "lattice energy" method doesn't work for all compounds, same is the case with Fajan's rule. These are theories which have been developed to explain the characteristics and make it somewhat believable to the general audience but we cannot compare all compounds using one theory or the other because each theory has its own drawbacks. ...

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